PSQI: Pittsburgh Sleep Quality Index

The Pittsburgh Sleep Quality Index (PSQI) is a 19-item self-report measure that evaluates sleep quality and disturbances over a one-month period. Validated tool for clinical sleep assessment and research.

What is the PSQI?

The Pittsburgh Sleep Quality Index (PSQI) is the most widely used clinical tool for assessing sleep quality. Developed by researchers at the University of Pittsburgh in 1989, the PSQI measures subjective sleep quality over the past month across seven components.

The 19 self-rated items generate scores for seven components: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction. Each component is scored 0-3, with the sum producing a global score ranging from 0-21.

A global PSQI score greater than 5 indicates "poor sleep quality" with high sensitivity and specificity for distinguishing good and poor sleepers. The PSQI is validated across clinical populations including insomnia, depression, PTSD, chronic pain, and sleep apnea.

Screening Tool, Not Diagnostic

The PSQI identifies poor sleep quality and its likely contributing domains. A full clinical evaluation — often including sleep studies — is required for definitive diagnosis of specific sleep disorders such as insomnia disorder or obstructive sleep apnea.

Public Domain

The PSQI is freely available for clinical and research use. No licensing fees are required, making it accessible for widespread adoption in healthcare settings.

How to Administer the PSQI

Self-Report Format

Patients complete the 19-item questionnaire independently, reflecting on their sleep patterns over the past month. Can be administered in-clinic or remotely via secure digital portals.

Administration Time

Typically takes 5-10 minutes to complete. Scoring requires calculating seven component scores and summing for a global score (0-21).

Regular Monitoring

Administer at intake and every 4-8 weeks during sleep treatment. The one-month timeframe makes monthly reassessment appropriate for tracking progress.

Instructions ask respondents to consider their sleep over the past month, providing a detailed view of sleep patterns rather than isolated nights.

Administration Best Practices

• Ensure patients understand the "past month" timeframe before starting
• Review component scores, not just the global score, to target specific sleep issues
• Combine with sleep diaries for detailed real-time sleep tracking
• Consider referral to sleep specialists if PSQI > 10 with severe daytime impairment

PSQI Scoring & Interpretation

Seven Component Scores

Each component is scored 0–3 (0 = no difficulty, 3 = severe difficulty). The sum of all seven component scores yields the global PSQI score (range 0–21). Higher scores reflect worse sleep quality.

Component Breakdown

Global PSQI score > 5 indicates poor sleep quality (sensitivity 89.6%, specificity 86.5%; Buysse et al., 1989).

Your Estimated Sleep Night

Items 1–4 together reconstruct a typical night's sleep pattern: the patient records their usual bedtime (item 1), how long it takes to fall asleep (item 2, used in Component 2), the time they wake up (item 3), and the actual hours of sleep obtained (item 4). From these, habitual sleep efficiency (Component 4) is calculated as:

Sleep efficiency (%) = (hours of actual sleep ÷ hours in bed) × 100

For example, a patient who goes to bed at 11 pm, takes 45 minutes to fall asleep, sleeps 5.5 hours, and rises at 7 am has spent 8 hours in bed — yielding a sleep efficiency of 69%. Sleep efficiency below 85% is generally considered clinically relevant and is a key target in cognitive behavioural therapy for insomnia (CBT-I).

Areas to Address

Reviewing component scores alongside the global score directs treatment. The following guide links high component scores to evidence-based intervention targets:

Clinical tip: Review individual component scores at every reassessment, not just the global score. Two patients can both score 9 with entirely different profiles — and entirely different intervention priorities.

Monitoring Treatment Response

Track global and component scores over time to demonstrate intervention effectiveness — for example, a falling sleep latency component after stimulus control therapy, or a declining sleep medication component during a supervised taper. A meaningful reduction in global score, sustained across repeated administrations, provides the most useful signal of treatment response.

When to Refer

Consider sleep specialist referral if:

• PSQI > 10 despite evidence-based behavioural interventions (a widely used clinical convention, not a validated severity tier)
• High sleep disturbance score combined with reported snoring or gasping (possible obstructive sleep apnea)
• Severe daytime dysfunction affecting occupational or social functioning

PSQI vs Other Sleep Assessment Tools

Different sleep assessment tools measure different aspects of sleep health. Understanding these differences helps you select the right tool for your clinical goals.

PSQI vs ISI: Sleep Quality vs Insomnia Severity

The PSQI is a broad-spectrum sleep assessment — use it when you need a full picture of sleep health across multiple dimensions. The ISI is focused on insomnia symptoms and their impact; use it specifically for insomnia screening and monitoring CBT-I (cognitive behavioural therapy for insomnia) treatment response. If sleep complaints are vague or you're screening for any sleep disorder, start with PSQI. If the patient clearly has insomnia, ISI is faster and more sensitive to treatment changes.

When to use PSQI: general sleep screening, multiple sleep concerns, research studies, detailed sleep disorder evaluation, or unclear diagnosis.

PSQI vs ESS: Sleep Quality vs Daytime Sleepiness

The PSQI and ESS measure opposite ends of the 24-hour sleep-wake cycle. PSQI assesses how well a patient sleeps at night; the Epworth Sleepiness Scale (ESS) assesses how sleepy they are during the day. They are complementary, not interchangeable. Use PSQI for insomnia-type complaints ("I can't fall asleep," "I wake up frequently"). Use ESS when patients report excessive daytime sleepiness, snoring, or suspected sleep apnea — ESS scores >10 warrant sleep study referral for possible obstructive sleep apnea.

Use both when a patient has sleep quality complaints AND daytime sleepiness. A high ESS combined with a high PSQI suggests a disorder such as sleep apnea may be disrupting nighttime sleep and causing daytime fatigue — a pattern that warrants polysomnography (sleep study) referral.

PSQI vs Actigraphy: Subjective vs Objective Sleep Measurement

PSQI and actigraphy provide different but complementary information. PSQI captures the patient's subjective experience of sleep, which directly relates to quality of life and mental health. Actigraphy provides objective data about actual sleep-wake patterns, useful when subjective reports may be unreliable (e.g., cognitive impairment, paradoxical insomnia) or when circadian rhythm data is needed. Standard practice is to use PSQI for routine screening and treatment monitoring, adding actigraphy when diagnosis is unclear, circadian disorders are suspected, or objective validation is required.

Patients who report poor sleep quality (high PSQI) but show normal sleep patterns on actigraphy may have paradoxical insomnia (sleep state misperception). This mismatch guides treatment toward CBT-I rather than sleep medications.

Documenting PSQI Scores in Clinical Notes

PSQI global and component scores belong in the Objective section of your clinical note. See our SOAP notes guide and Intake Notes guide for templates and examples.